Adding additional automatic weights to my original mesh without redoing it all
Mark the hands with a vertex group (we'll call it &quot;dtHands&quot;.)  Duplicate your mesh.  Autoweight your duplicate.  Give your original a data transfer modifier, targeting the duplicate, copying vertex groups on the basis of topology, limited by dtHands vertex group.  Hit &quot;generate data layers&quot; button as necessary.  Test deforms, possibly smooth out the border of dtHands group to make a more even transition.  Apply the data transfer modifier then delete the duplicate.